﻿using System;
using Microsoft.Extensions.Logging;
using GaussDB.Internal;

namespace GaussDB.BackendMessages;

[Serializable]
sealed class ErrorOrNoticeMessage
{
    internal string Severity { get; }
    internal string InvariantSeverity { get; }
    internal string SqlState { get; }
    internal string Message { get; }
    internal string? Detail { get; }
    internal string? Hint { get; }
    internal int Position { get; }
    internal int InternalPosition { get; }
    internal string? InternalQuery { get; }
    internal string? Where { get; }
    internal string? SchemaName { get; }
    internal string? TableName { get; }
    internal string? ColumnName { get; }
    internal string? DataTypeName { get; }
    internal string? ConstraintName { get; }
    internal string? File { get; }
    internal string? Line { get; }
    internal string? Routine { get; }

    // ReSharper disable once FunctionComplexityOverflow
    internal static ErrorOrNoticeMessage Load(GaussDBReadBuffer buf, bool includeDetail, ILogger exceptionLogger)
    {
        (string? severity, string? invariantSeverity, string? code, string? message, string? detail, string? hint) = (null, null, null, null, null, null);
        var (position, internalPosition) = (0, 0);
        (string? internalQuery, string? where) = (null, null);
        (string? schemaName, string? tableName, string? columnName, string? dataTypeName, string? constraintName) =
            (null, null, null, null, null);
        (string? file, string? line, string? routine) = (null, null, null);

        while (true)
        {
            var fieldCode = (ErrorFieldTypeCode)buf.ReadByte();
            switch (fieldCode) {
            case ErrorFieldTypeCode.Done:
                // Null terminator; error message fully consumed.
                goto End;
            case ErrorFieldTypeCode.Severity:
                severity = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.InvariantSeverity:
                invariantSeverity = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.Code:
                code = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.Message:
                message = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.Detail:
                detail = buf.ReadNullTerminatedStringRelaxed();
                if (!includeDetail && !string.IsNullOrEmpty(detail))
                    detail = $"Detail redacted as it may contain sensitive data. Specify '{GaussDBConnectionStringBuilder.IncludeExceptionDetailDisplayName}' in the connection string to include this information.";
                break;
            case ErrorFieldTypeCode.Hint:
                hint = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.Position:
                var positionStr = buf.ReadNullTerminatedStringRelaxed();
                if (!int.TryParse(positionStr, out var tmpPosition))
                {
                    exceptionLogger.LogWarning("Non-numeric position in ErrorResponse: " + positionStr);
                    continue;
                }
                position = tmpPosition;
                break;
            case ErrorFieldTypeCode.InternalPosition:
                var internalPositionStr = buf.ReadNullTerminatedStringRelaxed();
                if (!int.TryParse(internalPositionStr, out var internalPositionTmp))
                {
                    exceptionLogger.LogWarning("Non-numeric position in ErrorResponse: " + internalPositionStr);
                    continue;
                }
                internalPosition = internalPositionTmp;
                break;
            case ErrorFieldTypeCode.InternalQuery:
                internalQuery = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.Where:
                where = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.File:
                file = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.Line:
                line = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.Routine:
                routine = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.SchemaName:
                schemaName = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.TableName:
                tableName = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.ColumnName:
                columnName = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.DataTypeName:
                dataTypeName = buf.ReadNullTerminatedStringRelaxed();
                break;
            case ErrorFieldTypeCode.ConstraintName:
                constraintName = buf.ReadNullTerminatedStringRelaxed();
                break;
            default:
                // Unknown error field; consume and discard.
                buf.ReadNullTerminatedStringRelaxed();
                break;
            }
        }

        End:
        if (severity == null)
            throw new GaussDBException("Severity not received in server error message");
        if (code == null)
            throw new GaussDBException("Code not received in server error message");
        if (message == null)
            throw new GaussDBException("Message not received in server error message");

        return new ErrorOrNoticeMessage(
            severity, invariantSeverity ?? severity, code, message,
            detail, hint, position, internalPosition, internalQuery, where,
            schemaName, tableName, columnName, dataTypeName, constraintName,
            file, line, routine);

    }

    internal ErrorOrNoticeMessage(
        string severity, string invariantSeverity, string sqlState, string message,
        string? detail = null, string? hint = null, int position = 0, int internalPosition = 0, string? internalQuery = null, string? where = null,
        string? schemaName = null, string? tableName = null, string? columnName = null, string? dataTypeName = null, string? constraintName = null,
        string? file = null, string? line = null, string? routine = null)
    {
        Severity = severity;
        InvariantSeverity = invariantSeverity;
        SqlState = sqlState;
        Message = message;
        Detail = detail;
        Hint = hint;
        Position = position;
        InternalPosition = internalPosition;
        InternalQuery = internalQuery;
        Where = where;
        SchemaName = schemaName;
        TableName = tableName;
        ColumnName = columnName;
        DataTypeName = dataTypeName;
        ConstraintName = constraintName;
        File = file;
        Line = line;
        Routine = routine;
    }

    /// <summary>
    /// Error and notice message field codes
    /// </summary>
    internal enum ErrorFieldTypeCode : byte
    {
        Done = 0,
        Severity = (byte)'S',
        InvariantSeverity = (byte)'V',
        Code = (byte)'C',
        Message = (byte)'M',
        Detail = (byte)'D',
        Hint = (byte)'H',
        Position = (byte)'P',
        InternalPosition = (byte)'p',
        InternalQuery = (byte)'q',
        Where = (byte)'W',
        SchemaName = (byte)'s',
        TableName = (byte)'t',
        ColumnName = (byte)'c',
        DataTypeName = (byte)'d',
        ConstraintName = (byte)'n',
        File = (byte)'F',
        Line = (byte)'L',
        Routine = (byte)'R'
    }
}
